The 31-year-old American, who previously won at the 2016 Rio Games and in Tokyo in 2021, managed a season's best of 22.90 metres with his third effort for victory at the Stade de France.
Crouser's US teammate Joe Kovacs snatched silver with his sixth and last attempt of 22.15m -- the third time he has finished runner-up to his compatriot -- and Jamaican Rajindra Campbell took bronze despite registering the same distance.
Other athletes to have won two consecutive shot put golds are the American pair of Ralph Rose (1904, 1908), Parry O'Brien (1952, 1956), and Poland's Tomasz Majewski (2008, 2012)
But Crouser's victory -- the 20th time an American has won the event in 30 Olympics -- puts him in a different class.
"It definitely, I think, means the most out of all of them," said Crouser.
"I mean, kind of how Tokyo felt, fresh off a world record, felt like it was mine to lose.
"Tonight, I'm number three coming in on the performance list, and so it let me play a little bit more fast and loose.
"In Rio I was the new guy on the block, first year professional, so that one, I don't want to say it was lucky, but it was definitely the least appreciated for me.
"So this one it's definitely the sweetest victory out of all of them, overcoming the questions of if I would be able to get to this point again."
'Appreciate it more'
Crouser's victory is all the more remarkable given his injury woes this season.
He won the world indoor title in Glasgow in March, but since then has suffered two debilitating elbow injuries either side of tearing a pectoral muscle.
However, Crouser had shown before that injuries hardly affect his ability as he had won last year's world title only weeks after being diagnosed with deep vein thrombosis.
"So there's just the injuries this year, with the ulnar nerve entrapment, and the torn pec, and then the nerve issue again, made it kind of all the sweeter, made me appreciate it more."
Crouser, who will celebrate by going out with his family who are in Paris to share his victory, said he would probably wrap up his career by going for a fourth title in Los Angeles in 2028.
"The perfect end cap for me would be LA 2028, as an American athlete, retiring and hanging up the shoes on home soil," said Crouser, who was yet to don his trademark stetson in celebration.
LA, he said, "would be the first and only Olympic Games of my career in the US."
As for Kovacs, at 35 it is probably the two-time world champion's final tilt at the Olympic gold medal but he had few regrets.
"It's a great rivalry and I don't think I pushed him today, but I think that with that last throw I kind of made sure I didn't let these other guys sneak in there."
